Connect usb (legacy usb 2.0 port if you have one) with laptop powered off, power up while holding the win B keys down, keep holding them until you get a bios recovery screen.hopefully it will crisis recover your bios, some models use the all 4 arrows keys instead of win B NOTE: Remove the drive letter from your sisters HP_TOOLS partition when done copying files. It turned out that my BIOS-Battery (inside the laptop casing), was getting weak and needed replacement.I definitely did not want to be in a position where we were manually updating BIOS versions.Here is a solution to update your BIOS versions using a Configuration Manager task sequence. But after searching on the Internet and find there is a “crisis recovery” mechanism to recovery the BIOS even the CMOS don’t work. There are two model for Compaq CQ35 computers, so there are two . You may try one by one to see which model your computer use.You need to prepare a USB flash disk and another computer that is connected to the Internet (we need to download the BIOS image from HP). Format the USB flash disk’s filesystem to FAT16 on another computer.2. Remove the AC power and battery from the lapttop.5. After the laptop starts short beeping, release Win Key B.11.
Download the BIOS update file from HP’s website (an exe file). If the laptop keeps long beeping or beeping for more than 3 minutes, the recovery fails, possibly because of the wrong image file or the USB flash disk doesn’t work on the laptop.I tried to flash my HP Compaq CQ35-240TX’s BIOS to F.15 but unfortunately failed. When I restarted (powered off then boot again), this is no response any more: the hard disk and caps lock’s LED keep blinding. I will introduce the procedure to crisis recovery my HP Compaq laptop. (the file may be different depending on the model)4. Push the Power button as normal to power on the computer.10. I finally managed to recovery the BIOS with a help of USB flash disk. For my computer and the BIOS version I use, the two files are 306DF15. Actually this model can be found in “BIOS Setup” (we can’t start it as the CMOS is bad)3. FD to USB disk’s root directory and rename it to 306 Hold the Power Button for 5 seconds, then release.9.EDIT: I forgot to add that I have also tried extracting a BIOS file from the HP BIOS Update software downloads using Universal Extractor and putting it in a USB drive. The BIOS that I took from my sister's laptop was still in the USB once the installation was done.Once the USB drive was ready, I inserted it in my laptop and followed Moab's procedure (Win key b pressed until the screen pops up).